Mercury switch



H. O. PUTT MERCURY SWITCH July 24, 1934.

Filed July 5, 1932 lil() adjacent to which isa plug 29, of burnt Patented -July 24, 1934 UNITED STATES PATENT OFFICE l Adlake Company, of Illinois Elkhart, Ind., a corporation Application July 5, 1932, serial 1ra-620,198 4 claims. (o1. zou-97)l 'Ihis invention relates tomercury switches, and has for its principal object to facilitate the making of small openings for the passage of fluids ,to accurately time the operation 'of the switches.

The drawing shows the invention in connection with one type of mercury switch relay, in which:

Fig. 1 is a vertical section with the magnet energized;

Fig. 2 is a similar yView with the magnet deenergized;

Fig. 3 is an enlarged sectional View of one end of the displacer;

Fig. 4 is a plan view of the same; and

Figs. 5 and 6 are side elevation and plan view of a plug used to adjust the size of a. passage in the displacer.

But these specic drawings and the corresponding specic descriptionl are used for the purpose of illustration and disclosure only, as other applications within the spirit of the invention will occur to those familiar with this art.

The switch envelope 10 tube, with a pinch seal 11 at the top and a fiat base 12 in which the lead-in conductors 13 and 14 are sealed. 'Ihe conductor 14 extends a considerable distance into the envelope, and is enclosed within a glass sleeve 15 fused to the base. The conductors are equipped with electrodes 16 and 17, respectively. Within the tube is a charge of mercury 18, a displacer 19, two nonmagnetic springs 20 which cushion the movements of the displacer in shipping and handling, and also a gas fill, such ,as hydrogen, helium, and the like. l

The displacer is made of Swedish iron, or other magnetic material, so as to be shifted by the attraction of a magnet comprising a solenoid 21, wound on a spool 22, mounted between through the relay the arms of a yoke 23 and held by iron sleevesA 24, which also serve as mountings for the mercury tube, which is held against movement by a non-magnetic coil 25. The displacer is, generally speaking, a hollow cylinder having narrow flanges 26 at its ends cut away to permit free iiow of the fluid. ',Ihe bore 27 issubstantially cylindrical to near the top, where the wall takes the form of the frustum of a cone 28 asbestos fiber, hair, steel Wool, or the like. 'Ihe top is provided with a narrow passage to permit restricted ow of gas into and out of the bore is a cylindrical glass conditions that the device is to operate.

in response to a movement of the displacer withl respect to the magnet. ,I

For example, when the-magnet is deenergized the displacerdrops from the position shown in Fig. 1J toward the position shown in Fig. 2, causing the gas within the bore of the displacer above the mercury to be compressed, with the -result that the mercury is prevented from rising above the sleeve 15 to close the circuit with the electrode `17 until the desired delay has elapsed, the time being consumed by restricting the ilow of gas' from the interior of the displacer to the exterior;

In many types of switches the passage for gas must be made very accurately .to fractions of a thousandth of an inch, and the processes heretofore used for that purpose have been relatively expe'nsive. According to this invention a relatively large hole 30 is bored through the wall of the displacer. A cylindrical plug 31, of a size to t tightly in that hole, is rst prepared and then cut or ground away at one side, 32, at an angle to/the axis of the plug. In other words, a wedge-shaped strip is cut away, The plug is then inserted in the open ing `30 and pressed or driven until the clearance between the face 32 and the adjacent wall of the opening 30 is the size required under the method the displacers are made test, and the plugs 31 accurately displacers are sealed in the enpracticing this by a standard set beforev the velope.

It is much easier to fit a relatively large plug in a hole' than to form a very small hole to accurate size. Having fitted the plug in the hole and provided it with a varying cross-section,

nothing remains but to presser drive the plug back and forth until the orifice is at the exact size required.

As an example: With a displacer-1-1/2" long, 1-3/64ths" inside and 9/32nds" outside diam.- eter, I use a hole 1/16 in diameter and a plug 1/16" indiameter and 3/'16" long, `tapered as shown to 3/64" thickness. ."Y

I claim as my invention- 1. For use in ay mercury switch `of the class described, a hollow body having a large opening for liquid and a small opening for gas,th latter opening consisting of the wall of the opening, and a smooth-faced cylindrical plug tightly fitted in the opening and having a portion cut away at an angle to its axis. y

2. For use in a mercury clearance between switch of the class $1.10

, a smooth-walled plug which progressively and substantially uniformly changes the size of the opening as it is driven into the opening.

4. In combination with a time delay mercury switch, aNwall adapted to separate two bodies of gas of unequal pressure, said wall having an aperture through which gas may pass, and means for-Varying the effective size of the aperture; said means including a smooth-walled plug which progressively and substantially uni- `formly changes the size of the opening as it is driven into the opening.

l HARLIE O. PUTI. 

